The present invention relates to a pillow type bag sealed with a tape adhered to any portion of a surface of the bag, and easily openable by taking an end of the tape with fingers and pulling it, and a method for producing the same. In particular, the present invention relates to a pillow type bag laterally openable in the vicinity of a laterally fused area of the bag.
In Japanese Unexamined Patent Publication No. 7-76354, the present inventor has proposed a bag in which both side portions of a film thermally fusible in both faces thereof are arranged close to each other, and covered with a separation tape which is fused with outer faces of both side portions of the film to form a cylindrical tube. Both end portions of the tube are then laterally fused. This bag can be easily opened by grasping an end of the tape with fingers and pulling it.
However, according to the above-mentioned technique, the resulting bag is longitudinally opened. Bags are preferably longitudinally opened in some cases, and preferably laterally opened in the other cases, depending on the contents thereof. When the lateral opening is preferred, the above-mentioned technique can not achieve the desired results.
Recently, automatic filling and closing machines have gained wide usage for producing a flexible package. In particular, a film is supplied while being longitudinally fused, and the respective steps of filling the longitudinally fused film with the contents, laterally fusing the film and cutting the laterally fused area are performed in sequence. There is one longitudinally fused area on the back of the resulting bag and no longitudinally fused area on a surface of the bag, and both the upper and lower ends are laterally fused. This is a so-called pillow type bag, and has widely prevailed.
If this pillow type bag could be opened at its upper portion in a direction approximately parallel with the laterally fused area by pulling the tape, such bag would demonstrate both desirable sealing performance and ease of opening. However, it was heretofore difficult to produce such a bag even by the technique described in Japanese Unexamined Patent Publication No. 7-76354.
Moreover, for the contents, it is generally desirable to laterally open the sealed bag from one end thereof in the longitudinal direction in many cases. Accordingly, a bag has been desired which can be easily opened in parallel with a laterally fused area by pulling an opening fusing tape.